The Check valve that is inline to the tank from the compressor also has a small line to the cutoff/cuton relief.
Part No. 1503 2515 00. I can not for the life of me find an NSN for this part. It looks like an average brass elbow fitting, but it acts like a simplified check valve
TLTR: Need an NSN for Part No. 1503 2515 00.
Thank You for any help.